/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
#include <iostream>

using namespace std;

class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
		if(!head || !head->next){
			return head;
		}
		ListNode * cur = head;
		while(cur->next){
			if(cur->val == cur->next->val){
				ListNode * tmp = cur->next->next;
				delete(cur->next);
				cur->next = tmp;
			} else {
				cur = cur->next;
			}
		}
		return head;
    }
};
